1. Field of the Invention
This invention relates to an apparatus for dyeing a fabric material, more particularly to a dyeing apparatus capable of dyeing an elongate loop of fabric material while in recycling flow in contact with a dye liquid.
2. Prior Art
Generally widely known in the art of fabric dyeing are beam dyeing machines, a typical example of which comprises a dye beam having a porous or otherwise permeable cylinder on which a fabric such as in the form of elongate tape is wound to an uniform thickness. There are however limitations to the thickness to which the fabric can be wound on itself in order to ensure adequate and uniform dyeing through the medium of a dye liquid injected forcibly through the wound fabric material. To compensate for such limitations, design considerations would be required to provide a dye beam with a cylinder of larger diameter and increased width, which would literally give rise to equipment size. Conventional dye beams would otherwise require laborious start-up preparations and repeated after-dye take-up and rewind operations.
The prior art beam dyeing would further involve difficulty in achieving take-up of the fabric material in uniform layer throughout the length of the beam and also difficulty in evening out the dye intensity throughout all dimensions of the wound material, i.e. the outer layer, inner layer, opposite ends and center of the material, resulting in speckles or irregularities in the dye finish which would be difficult to eliminate even by rotating the beam or changing the dye flow.
The foregoing difficulties inherent in the beam dyeing machines can be significantly alleviated by a liquid flow type dyeing machine having a dyeing vessel of a relatively large capacity capable of handling a relatively wide fabric material which is allowed to fold on itself while moving through a stream of dye liquid. Whilst this latter machine is satisfactory in treating large width materials, it would present a problem with a narrow strip of material such as a slide fastener tape which is apt to orient out of its normal folded condition under the influence of irregular dye flow and get entangled, twisted or even clogged to plug up the passage of the material.